Polymer coated papers and water resistant sheathing materials are known to be useful in the construction industry, for preventing the infiltration of air and water to the interior of a building while allowing the outward passage therethrough of moisture vapor. Such materials may be flexible and used as building "wraps," or may be rigid and used as structural or decorative panels in the exterior walls or roofs of buildings.
Typical breathable materials comprise a flexible or rigid substrate, overlaid with a polymer layer which has been mechanically or electrically perforated, embossed, or stretched to produce "holes" therethrough, said holes being small enough to substantially prevent the flow therethrough of air and water, but large enough to allow the passage of moisture vapor. An example of a breathable material, comprising a resin blended with inorganic fillers which is then extruded into a film and biaxially stretched or stretched in a single direction is EXXAIRE from Exxon Inc.
While monolithic breathable polymer films are known in the prior art, it is also known that such films, when applied to substrates utilizing the heat and pressure associated with conventional lamination processes, often delaminate from the supporting substrates.
It would be desirable to prepare a coated substrate having a high MVTR, wherein the resultant laminate would retain its structural integrity while preventing the flow therethrough of air and water but allowing the passage therethrough of moisture vapor.